The effect of Autoclaved Aerated Concrete on the Survival and Growth of Launaea cornuta and Sporobolus jacquemontii grown in Heavy Metal Polluted Soils: A Greenhouse Study

Abstract

This study aimed at evaluating the effect of Autoclaved Aerated Concrete (AAC) (waste from construction activities) on the survival and growth of Launaea cornuta (Oliv & Hiern) C. Jeffrey and Sporobolus jacquemontii K., grown in heavy metal polluted soils using pot experiments. Changes in soil pH, extractable metal content, survival, growth, biomass production and increase of number of leaves in plants were determined. Results show that the plants survival rate in heavy metal contaminated soil increased with increase of AAC. Treatment with 33.94t/ha of AAC has shown better growth of both L. cornuta and S. jacquemontii (number of leaves developed, plant height and biomass) as compared to the 22.63t/ha of AAC. The  AAC amendments provided extra sorption sites thereby reducing the bioavailable portion of the metal. Moreover, it raised the soil pH (from 6.8 to 7.8.) favoring precipitation of the metal ions in the soil, thereby reducing metal toxicity to plants. The present study has established that soil  amendment by addition of AAC enhanced plant growth in soils polluted with elevated heavy metal levels, as well as minimizing the bio-available portion for plant uptake. These effects suggest that AAC has the potential for use in phytoremediation of heavy metal contaminated soils.

Key words: AAC, heavy metal, soil, stabilizing agents, pollution, toxicity, L. cornuta, S. jacquemontii